The invention concerns an rpm governor for fuel injected internal combustion engines--especially diesel engines--which has an rpm-dependent, automatic regulating member that is connected with the feed control member of the fuel injection pump by means of an intermediate lever, and which operates on the control lever of an rpm-controlled starting device only during non-operation of the governor at rpm's lower than the idling rpm. This lever is coupled to a stop, and is located in the governor housing. In the normal operational range of the governor, the stop which limits the volume to the operational maximum can be moved out of the way of a counter-stop connected to the feed control member, and the feed control member is capable of being shifted into a position, in which the fuel injection pump supplies a quantity of fuel (start quantity) which exceeds the operational maximum. The fuel injection pump is connected to a return spring which holds the control lever in its original position, not touching the regulating member, when it is not in operation.
An rpm governor is already known (Austrian Pat. No. 185,613), whose starting device controls an automatically increased starting quantity, by means of a control lever acted upon by regulating member and coupled to a stop, during non-operation of the engine and at rpm's lower than the lowest idling rpm. The increased starting quantity is cut off after the first reving of the engine and the limitation to the maximum operational quantity becomes effective. This rpm governor is employed with special effectiveness in fast starting diesel engines, but has the disadvantage that this increased starting quantity is released and controlled during every start, i.e., even when the engine is warm. Rapid starting diesel engines need, however, the increased starting quantity only in starting when the engine is below a predetermined operational temperature, so that by the use of the automatic starting device in a warm engine, too much fuel is injected, and the exhaust gases unnecessarily exceed the values for the allowable exhaust density (smog limits).
It is further known with injection pumps with rpm governors, but without automatic starting devices (FIGS. 1-3 of British Pat. No. 529,671), to limit the position of the feed control member of the fuel injection pump in the direction of greater supply quantities by stops controlled by a thermostat. These stops depend only on the temperature. The known governor contains no means for an automatic, rpm-controlled increased starting quantity release and subsequent decrease, so that the increased starting quantity is maintained too long, until the operational temperature is attained. In rapid starting diesel engines, this leads to excessive exhaust fumes.
In a special exemplary embodiment of the previously mentioned rpm governor (FIG. 4 of British Pat. No. 529,671), the stop is activated by a magnet located in the starting circuit which can be shut off by a temperature-dependent bimetallic switch. Apart from the forces that disadvantageously load the armature of the magnet, this starting device is expensive and can be unnecessarily activated by a bypass of the thermostat switch or of the starter even during operation of the motor vehicle. In this manner it may be true that a corresponding rise in performance is attained, but it also entails as an unavoidable consequence damage or destruction of the engine or of the assembly attached to the engine. In addition, during an adjustment of the maximum quantity in the governor, the position of the magnet must also be adjusted, which leads to an expensive construction.